794 research outputs found

    On autonomic platform-as-a-service: characterisation and conceptual model

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    In this position paper, we envision a Platform-as-a-Service conceptual and architectural solution for large-scale and data intensive applications. Our architectural approach is based on autonomic principles, therefore, its ultimate goal is to reduce human intervention, the cost, and the perceived complexity by enabling the autonomic platform to manage such applications itself in accordance with highlevel policies. Such policies allow the platform to (i) interpret the application specifications; (ii) to map the specifications onto the target computing infrastructure, so that the applications are executed and their Quality of Service (QoS), as specified in their SLA, enforced; and, most importantly, (iii) to adapt automatically such previously established mappings when unexpected behaviours violate the expected. Such adaptations may involve modifications in the arrangement of the computational infrastructure, i.e. by re-designing a different communication network topology that dictates how computational resources interact, or even the live-migration to a different computational infrastructure. The ultimate goal of these challenges is to (de)provision computational machines, storage and networking links and their required topologies in order to supply for the application the virtualised infrastructure that better meets the SLAs. Generic architectural blueprints and principles have been provided for designing and implementing an autonomic computing system.We revisit them in order to provide a customised and specific viewfor PaaS platforms and integrate emerging paradigms such as DevOps for automate deployments, Monitoring as a Service for accurate and large-scale monitoring, or well-known formalisms such as Petri Nets for building performance models

    Análisis de los diferentes tipos de desvulcanizado en la caracterización de nuevos materiales elastoméricos formados por la mezcla de estireno butadieno-caucho natural y mezclados con neumáticos fuera de uso (GTR)

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    En este artículo se propone la creación de un nuevomaterial útil para la industria a partir de la mezcla con rodillos de dos elastómeros vírgenes al 50% (estireno-butadieno (SBR) y caucho natural (NR)) con neumáticos fuera de uso (GTR). Estos neumáticos han sido previamente desvulcanizados siguiendo diversas técnicas, las cuales serán analizadas en este artículo, para posteriormente realizarse su mezcla con el elastómero virgen SBR/NR y los aditivos correspondiente, volviéndose a vulcanizar este nuevo material con el fin de que alcance las propiedades mecánicas, térmicas y de estructura que permitan su utilización en la industria. Concretamente se han analizado tres tipos de muestras; una primera formada por el elastómero virgen (SBR/NR), una segunda añadiendo al SBR/NR, GTR en la proporción de 20 phr (parts perhundred rubber), y una tercera añadiendo al SBR/NR, GTR en la proporción de 40 phr (en los ensayos mecánicos se han utilizado más porcentajes, con el finde proporcionar mayor fiabilidad en los resultados). El GTR recibido ha sido desvulcanizado aplicando diferentes técnicas: sin desvulcanizar (dn); desvulcanizado mecánicamente (dm); desvulcanizado química y mecánicamente (dcm); y desvulcanizado mediante microondas (dmw). Todos estos compuestos han sido ensayados con diferentes pruebas; Mecánicas, de Densidad de entrecruzamiento, de Análisis Térmicogravimétrico y del Ensayo de Microscopía

    Complex organic molecules in comets C/2012 F6 (Lemmon) and C/2013 R1 (Lovejoy): detection of ethylene glycol and formamide

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    A spectral survey in the 1 mm wavelength range was undertaken in the long-period comets C/2012 F6 (Lemmon) and C/2013 R1 (Lovejoy) using the 30 m telescope of the Institut de radioastronomie millim\'etrique (IRAM) in April and November-December 2013. We report the detection of ethylene glycol (CH2_2OH)2_2 (aGg' conformer) and formamide (NH2_2CHO) in the two comets. The abundances relative to water of ethylene glycol and formamide are 0.2-0.3% and 0.02% in the two comets, similar to the values measured in comet C/1995 O1 (Hale-Bopp). We also report the detection of HCOOH and CH3_3CHO in comet C/2013 R1 (Lovejoy), and a search for other complex species (methyl formate, glycolaldehyde).Comment: Accepted for publication as a Letter in Astronomy and Astrophysic

    Gray matter correlates of cognitive ability tests used for vocational guidance

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    <p>Abstract</p> <p>Background</p> <p>Individual differences in cognitive abilities provide information that is valuable for vocational guidance, but there is an ongoing debate about the role of ability factors, including general intelligence (<it>g</it>), compared to individual tests. Neuroimaging can help identify brain parameters that may account for individual differences in both factors and tests. Here we investigate how eight tests used in vocational guidance correlate to regional gray matter. We compare brain networks identified by using scores for ability factors (general and specific) to those identified by using individual tests to determine whether these relatively broad and narrow approaches yield similar results.</p> <p>Findings</p> <p>Using MRI and voxel-based morphometry (VBM), we correlated gray matter with independent ability factors (general intelligence, speed of reasoning, numerical, spatial, memory) and individual test scores from a battery of cognitive tests completed by 40 individuals seeking vocational guidance. Patterns of gray matter correlations differed between group ability factors and individual tests. Moreover, tests within the same factor showed qualitatively different brain correlates to some degree.</p> <p>Conclusions</p> <p>The psychometric factor structure of cognitive tests can help identify brain networks related to cognitive abilities beyond a general intelligence factor (<it>g</it>). Correlates of individual ability tests with gray matter, however, appear to have some differences from the correlates for group factors.</p

    Importance of Vanadium-Catalyzed Oxidation of SO2 to SO3 in Two-Stroke Marine Diesel Engines

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    Low-speed marine diesel engines are mostly operated on heavy fuel oils, which have a high content of sulfur and ash, including trace amounts of vanadium, nickel, and aluminum. In particular, vanadium oxides could catalyze in-cylinder oxidation of SO2 to SO3, promoting the formation of sulfuric acid and enhancing problems of corrosion. In the present work, the kinetics of the catalyzed oxidation was studied in a fixed-bed reactor at atmospheric pressure. Vanadium oxide nanoparticles were synthesized by spray flame pyrolysis, i.e., by a mechanism similar to the mechanism leading to the formation of the catalytic species within the engine. Experiments with different particle compositions (vanadium/sodium ratio) and temperatures (300–800 °C) show that both the temperature and sodium content have a major impact on the oxidation rate. Kinetic parameters for the catalyzed reaction are determined, and the proposed kinetic model fits well with the experimental data. The impact of the catalytic reaction is studied with a phenomenological zero-dimensional (0D) engine model, where fuel oxidation and SOx formation is modeled with a comprehensive gas-phase reaction mechanism. Results indicate that the oxidation of SO2 to SO3 in the cylinder is dominated by gas-phase reactions and that the vanadium-catalyzed reaction is at most a very minor pathway

    Construction of data streams applications from functional, non-functional and resource requirements for electric vehicle aggregators. the COSMOS vision

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    COSMOS, Computer Science for Complex System Modeling, is a research team that has the mission of bridging the gap between formal methods and real problems. The goal is twofold: (1) a better management of the growing complexity of current systems; (2) a high quality of the implementation reducing the time to market. The COSMOS vision is to prove this approach in non-trivial industrial problems leveraging technologies such as software engineering, cloud computing, or workflows. In particular, we are interested in the technological challenges arising from the Electric Vehicle (EV) industry, around the EV-charging and control IT infrastructure

    Optimal interactions of light with magnetic and electric resonant particles

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    This work studies the limits of far and near-field electromagnetic response of sub-wavelength scatterers, like the unitary limit and of lossless scatterers, and the ideal absorption limit of lossy particles. These limit behaviors are described in terms of analytic formulas that approximate finite size effects while rigorously including radiative corrections. This analysis predicts the electric and/or magnetic limit responses of both metallic and dielectric nanoparticles while quantitatively describing near-field enhancements.Comment: 9 pages, 8 figures, 2 table
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